<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>1_引出生命周期</title>
</head>
<body>
    	<!-- 准备好一个“容器” -->
	<div id="test"></div>
	
	<!-- 引入react核心库 -->
	<script type="text/javascript" src="../js/react.development.js"></script>
	<!-- 引入react-dom，用于支持react操作DOM -->
	<script type="text/javascript" src="../js/react-dom.development.js"></script>
	<!-- 引入babel，用于将jsx转为js -->
	<script type="text/javascript" src="../js/babel.min.js"></script>
    <script type="text/babel">
        class Life extends React.Component{

            state= {
                opacity:1
            }
            // 组件挂载完毕
            componentDidMount(){
                // 组件挂载完毕
                console.log('componentDidMount')
                this.timer =setInterval(()=>{
                    var {opacity} =this.state
                    opacity-=0.1
                    if(opacity<=0) opacity=1
                    // this.setState({opacity:opacity})
                    this.setState({opacity})
                },200)
            }
            // 组件将要卸载的时候
            componentWillUnmount(){
                console.log('componentWillUnmount')
                clearInterval(this.timer)
            }

            death = () => {
                // 卸载组件
                ReactDOM.unmountComponentAtNode(document.getElementById('test'))
            }
            // 初始化渲染,状态更新之后
            render() {
                return (
                    <div>
                        <h2 style={{opacity:this.state.opacity}}>React学不会怎么办?</h2>    

                        <button onClick={this.death}>不活了</button>
                    </div>
                )
            }
        }
        // 渲染组件
        ReactDOM.render(<Life />,document.getElementById('test'))
    </script>
</body>
</html>